There is often need to construct seals within underground passageways such as mine drifts or tunnels. Since access to the seal site is usually hazardous and often times impossible, there have been developed a number of techniques to construct such seals remotely from the surface. Patents illustrating developed methods for remotely constructing seals include U.S. Pat. Nos. 3,421,587, 3,469,405 and 3,583,165.
Seals are constructed within underground mine workings, especially coal mine workings, for two major purposes. First, remote sealing has been used to isolate a fire area within both active and abandoned coal mines so as to control and extinguish the fire. Remote sealing techniques also are useful to control or divert acid mine water in order to prevent or minimize pollution of surface waters. Remote sealing techniques presently employed become extremely cumbersome and difficult to implement in deep mines; those mines whose workings are a few hundred to a few thousand feet below the surface. Techniques such as those disclosed in the Heavilon et al patent, U.S. Pat. No. 3,421,587 in which dry fly ash is pneumatically injected through bore holes into the mine workings, cannot seal a passage having a significant (greater than about 20 to 50 gpm) water flow in the passage. Flowing water simply channels through the fly ash as it is emplaced and maintains an open flow passage along the floor area even if the mine passage is filled to refusal with fly ash.
My invention provides a technique for remotely constructing seals in underground passages in the presence of water flowing therein. Seals can be constructed to withstand a large hydraulic head even in the presence of relatively high velocity, large volume water flows.